In a light emitting element using a nitride-based semiconductor, a nitride-based p-type semiconductor layer has lower electrical conductivity than an n-type semiconductor layer. As a result, electric current is not effectively spread in the p-type semiconductor layer in the horizontal direction, thereby causing current crowding at a specific portion of the semiconductor layer. If electric current is concentrated in the semiconductor layer, a light emitting diode can become susceptible to electrostatic discharge and can suffer from current leakage and efficiency drooping.
By uniformly distributing electric current in the entire light emitting region, the light emitting element can have improved luminous efficacy while reducing heat generation due to current crowding, thereby improving lifetime and reliability of the light emitting element.
Thus, a technique of forming a transparent electrode such as ITO and a current blocking layer on a p-type semiconductor layer in order to efficiently spread electric current has been disclosed in the related art. However, there is a limit in uniformly spreading electric current to the entire p-type semiconductor layer with only the current blocking layer and the transparent electrode. In addition, when a wire is bonded to a p-type electrode, the wire can be disconnected or the p-type electrode can be peeled off due to poor adhesion between the transparent electrode and the p-type electrode. As a result, the light emitting element has a high defect ratio due to defects around the p-type electrode and suffers from deterioration in reliability and production yield.
Moreover, various techniques have been disclosed for arranging a p-type electrode and an n-type electrode each having an electrode pad and an electrode extension in various ways in order to efficiently spread electric current upon operation of the light emitting element. However, due to light loss caused by absorption of light into the electrodes, there is a limitation in increasing current spreading efficiency through change of electrode arrangement.